I'll put it this way: I went to a top business school (which cost a lot more than $3000), and my finance professors were former traders, federal reserve governors, investment bankers, algo traders, etc. Without exception, they recommended a buy and hold strategy for non-institutional investors. Buy companies you believe in (or better yet, index funds), and hold them until you need the money. And this was in classes where they were teaching us investment strategies! The game is rigged against you; as an individual investor your information will always be 3-5 seconds out of date, and your trades will get thrown in the back of the queue behind the institutional investors. Any strategy that relies on market timing is doomed before you even start.
Professional traders (hedge funds, etc) can get away with risky strategies because they're balancing risk. For every insanely risky, 30x leveraged trade they make, they also hold metric fuck tons of US treasuries. You also never invest in one hedge fund; you invest in 30 or 40 hedge funds because most will lose money. The guys running the funds make their money off of fees because the return of the funds is usually based on economic factors more than 'alpha'.
Trading has changed a lot since the 40s and 50s. Modern finance wasn't really invented until the 80s as the relationship between debt and equity became much more fluid. If you really want a proper investment education, I would suggest a real education in the form of a computational finance degree as offered by many of the top quant business schools (CMU, MIT, etc.) There you can learn about the leveraged trading strategies that HFTs and algo traders use, why they work, and how to exploit them.
The big traders have a word for individuals who try to beat the market: suckers. There is no arbitrage, and even when there is, someone else will beat you to it because your access to the market is inferior to theirs. It's fundamentally unfair, but it's what happens when you have a revolving door between the federal reserve, the SEC and the top investment banks. You're playing a game with asymmetric information from the losing position against very skilled players. If you beat them, it's dumb luck. You're not going to be able to do it consistently.
The guys hosting seminars on investment strategy have found a way to consistently make money: by hosting seminars on investment strategy and charging $3000 to $5000 to attendees. If they had a truly ironclad way to make money consistently in the market, they wouldn't need the money from the seminars because they would be pulling in tens/hundreds of millions a year running a hedge fund or prop trading group.